PD-168077 maleate

PD-168077 maleate is a selective dopamine D₄ receptor agonist, with a K_i of 9 nM. IC50 & Target:Ki: 9 nM (Dopamine D₄ receptor)^[1]. In Vitro:PD-168077 is one of the first agents to be identified as putative selective D₄ agonists. It shows >100-fold selectivity over other members of the D₂-like receptor family and over their D₁-like counterparts; PD-168077 shows a 20-fold selectivity over α₁, and α₂, a 45-fold selectivity over 5-HT_1A, and a 460-fold selectivity over 5-HT_2A receptors; PD-168077 evidences intrinsic activity at the D₄ receptor in terms of quinpirole-like inhibition of forskolin-stimulated cAMP accumulation or stimulation of [³H]thymidine uptake in CHO cells expressing the human D₄ receptor^[1]. In the PD-168077-treated cell, p-CaMKII exhibits a significantly increased clustering at synaptic sites, as indicated by the enhanced colocalization with PSD-95^[2]. In Vivo:PD-168077 (0.2-25.0 mg/kg) dose-dependently induces locomotion, which takes an unusual and characteristic ”shuffling” form with uncoordinated movements together with yawning, and episodes of myoclonic jerking; grooming, and rearing are reduced^[1].